Tournaisian Neptunian Dykes and Their Conodont Fauna from Dalnia in the Hol!} Cross Mts
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acta gaologlea polonica Vol. 23. No. 1 Warszawa 1973 MICHAL SZULCZEWSKI Famennian -Tournaisian neptunian dykes and their conodont fauna from Dalnia in the Hol!} Cross Mts ABSTRACT: Neptunian dykes containing a unique fossil assemblage were found in ' the Upper Devonian limestones of a l'eef-oomplex on the Dalnia HiLl in the Holy Cross lVIts. Fissures df'the tectonic origin were opened and filled under subaqueous conditions. The cOIlodont fauna they 'oontain indicates that a repeated filling and re-opening of the fissures took place in the Famennian and Toumaisian. The filling of a main dyke and ,the fauna it contains correspond to a condensed sequence depo sitedona submarine rUle. The reconstructed outline of the area of a condensed sedimentation ,in the Famennian and TOlll'naisian approoximately coincides with the outline of a dead Frasnian table reef. The trace of fa'cial boundaries in the Upper Devonian and Tournaisian is toa considerable degree determined by a 'block-faulting simultaneous with 'the sedimentation. The facies pattern here presented seems to exert a 'certain influence on la'ter, pc:Jst-Carlboni:ferous tectonics. The paleontological part of the present paper inc1udesa systematic des'cription of 29 conodont'species, mostly Tournaisian ones, which have not so far been described from the Lower Carboni- feroous of the Holy Cross Mts. INTRODUCTION In 19:68, a new locaHty otf abuillldant and unique fossil fauna was disCOV'eTed in the 'course of work on the stratigraphy and sedimentation of 1lhe Upper !Devonian in the'WesteT1Il /part of the Holy Cross Mts. The locality is situated in the western part of the Kadzielnia range otf the Frasnian, at the Dalnia Hill 0IIl the .outskirts of Kielce. This Frasnian chain belongs to the southern limb of the Kielce syncline 'connecting it With the Dyminy anticline ,<cf. Fig. 1) situated to the south. PreliminaTY information on the locality has been given earlier (Szu1czewski 1971, pp. 63-64). This locality on the one hand has sU'Pplied a rich collection of ,fossils, most of them so far unknown from the Holy Cross Mts or being 16 MICHAl. SZULCZIDWSKI quite new taxa and, on the oth€l', its nearly entire fauna occurs in a spe cific geological situation as it is contained in a neptunian dyke. The presence of :the neptunian dykes rich in fossils throws a new 'light on several general, 'Paleogeographic and pa:leotectonic problems. The malIlil1er. of tthe occurrence of fossils iJ:l~nders, however, to a considerable extent a stratigraphic analysis and in -a way decreases the ·stratigraphic impor tance of the find. The material of the dykes does not display a distinct stratification and fauna varying in age is mixed in it, Famennian and TOUI'naisian forms occurring as well among the fossils. In 1969'-1971, these fossils were exploited by the writer and, partly, Doc. A. Stasiilska from the Polish Academy of Sciences. The elabOration of the material collected was .UIIldertaken Iby specia'lists from the Paleozoological Insti tute, Polish Academy of Sciences. A considerable pa-rt of the paleonto logical materials has already -been studied and their desoriptions are being publiShed in the present volume of the ACTA GEOLOGICA POLONICA (Osm6lska 1973, Stasiilska 1973, Fedorowski 1973). Docent H. Osm61Slka elaborated the entire collection of trilobites and Docent A. Stasiilska all the taibulates collected. Docent J. Fedorowski's paper oonceI'ns only part of the rugose corals. The rest of them, about 1,500 specimens, remainiJng at the disposal of Professor M. R6zkowska and Docent J. Fedoro'Wski, will be successively presented as further parts of the deseription .of fauna from DaItnia. Relatively few holothurian sclerites from that locality, have enriched a collection which makes the subject of a separate description, also in the present volume of the ACTA GEOLOGICA POLONICA (Matyja, Matyja & Szukzewski 1973). Acknowledgements. The wdter's thanks aTe extended to Docent H. Osm6lska, Docent A. Stasinska and Docent J. Fedorowski for their taking the trouble IOf -the description of fauna from DaJ.nia and for a discussion of stratigraphic and facies problems dealt with in the paper. The writer feels also indebted to Professor M. R6z kOWS'ka, now elaborating considerable part of corals from Dalnia, for giving pre liminary information on w'hi'Ch 'Chara<eteristies of the assemblage of corals have been based. NEPTUNIAN DYKES The neptunian dykescontainilng -a rich faUlIla occur (Fig. 2) in the top of the Dalnia Hill. They appear in a section which approximates the horizontal one and, therefore, they are visiJble "in plan". The dykes are well exposed as the result of the exploitation of limestone ina small rural quarry. Unfortunately, the exogenic ·a01d exploitation processes removed considerable part of the dykes. The neptunian dykes (Fig. 2B) cut through the Upper DeV'OlIlian oolitic limestones, Which aTe thkk -bedded and have dips of 30° and strike of 32°. The dykes run in principle ACTA GEOLOGICA POLONICA, VOL. 23 M. SZULCZ.EWSKI, FIG. 1 . A B o 1 2 3 4 5km I General map of Poland (A) and geological sketch map (B) of the western part of the Holy Cross Mts (after Czarnocki, 1938; simplified _ cf. Szulczewski 1971, Text-fig. 1) showing location of the Dalnia Hill (arrowed) and other sections dkcussed in th present paper (bold-faced). The remaining profiles and iheir abbreviations are the same as used in the previous paper (Szulczews:k:i 1971) I Cambrian, Ordovician and Silurian, 2 Lower and Middle Devonian, 3 Frasnian (fT) and Famennian (fa), 4 Lower Carboniferous, 5 post-Varlscan cover (Zechstein _ Upper Cretaceous) NEPl'UNrAN DYKES AND THEIR CONODONT FAUNA FROM DALNIA 17 parallel to the strike of oolitic 'limestones and penetrate them nearly vertically. The ll1etwOl"lk of dykes consists of two main dykes parallel to each other and separated bya 50 cm .- wide ledge of the oolitic limestoll1e cut by several small ;perpendicular dykes (Fig. 2A), 'which vary in width within limits of severa·l scores of centimeters. The smaUdy'kes are a few mm 'to a few cm wide. They are tortuous and either cOIl1nect the two main dykes, 'Cutting through the oolitic limestone of the ledge which divides them, or penetrate into the outer parts of this limestone. The fissures are filled with: (1) a pink to green marly limestone; (2) a gray crinoid limestoll1e; (3) a gray-g~een organodetritall limestone locally containing intTa clasts of a pink marly limestone; (4) black and alive-green clayey shales. A . 'e': ..... .. .. ' .' .' :. : . : . '. '. ~" . ...... ..... : '., . o fm I I Fig. 2 Sketch plan of the outcrop (fragment) with neptunian dykes (A) and magnified section (B -atlong k-m in A) through the oolitic iimestones cut by neptunian dykes at Dalnia 1 ool.j.tic limestones, 1I neptunilllll dykes, :I calcite veins; circled numbers denote the conodont samples 2 18 MICHAl. SZULCZEW·SKI . The clinoid limestone has been found only as a small lens sep,ara tely emlbedded in oolitic limestones (Fig. 3). The clayey shales have been found only in the waste. On the other hand, the pink or greenish marly limestone is absolutely predominant in the filling of both main dykes. In the northern dyke it is the only type of deposit, but it does notcOtntain any macrofOSSils, which OICour, however, in the limestone of this type in the southern dyke (corals, brachiapocis, 'trilobites, cephalapods). The marly limestone a'lso makes up a filling of all small dykes. The gray-green organodetrltallimestone, probably exploited already, occurs in very small amounts. Most specimens come from the waste, that is, 'a 'limestaneoonsistitug 'primarily of fragmentary trilobites and a crinoid detritus, with intraclasts of a pink marly l:imesoone, identical with that described above, which are embedded in it. The houndary between the two rocks, although visible in detached blocks only, is distinctly sedi mentary (erosional) in character. It also indicates that the organodetrital limestone is older than the marly one. The filling of the main southe:rn dyke prohably also contained at first a thin 'layer af red clay ahoundinlg in 'corals, as indicated by a rich occurrence ofexcel'lently separated corals accumulated in one place in the waste. It seems very unlikely that they could be so accurately sepa- o 10cm L....--....J Fig. 3 Detailed section showing position of thecrlnoid limestone in the neptunian dykes at Dalnia 1 oolitic limestones - bedrock of the ,neptunian dykes, 2 crinoi<l limestone in one of the uep1nmiall dykes, '3 marly Ilmestone in other dykes; circled numbers denote the cono<lont samples NEPTUNIAN DYKES AND THEIR CONODONT FAUNA FROM !DALNIA 19 rated from mar'ls by weathering. The red clay alone is clearly visi"ble in the waste, but there is no certainty if at least part of it is not a Ikal"st -weatherilng waste. GENERAL CHARACTERISTICS OF THE MACROFOSSIL ASSEMBLAGE ConodOllits and corals make up a preddminant element of the collection under study, with trilobites being also abundant. Other fOssi'ls as cepha'lo:poids, brachiopods and· crinoids (except for a lens of crimoid limestone) are ~are. Concise cha:racteristics O!f individual groups, in parti cular corals most of which are now only being studied, wiN he presented as follows. Corals. Rugose and 'tabulate corals, as wen as heterococals are present in the ,collection. The first of them make up about 90 per cent of a'll corals. The heterocorals are the least numerous and rugose corals occur only as so'litaryforms. No calonialforms have bee:n found. For this reason, as weN 'ag due to their smaN size and lack of dissepiments, they are of the type of the Cyathaxonia fauna (sensu Hill 1938, p. 5). The genera Cyathaxonia Michelin, N eaxon Kullmann, Pseudomicroplasma Soshkina, as well as metriophylloid, and cystophylloid forms predominate among them.